Epigaeic Formicidae assemblages in the surroundins of the National Park of Chapada Diamantina, Bahia, Brazil

Abstract

Ants at four localities were studied in the surroundins of the National Park of Chapada Diamantina, central region of the State of Bahia, Brazil. Vegetation belongs to the Atlantic forest biome (Sazonal Semideciduous Forest), but it is regionally surrounded by other vegetation formations, mainly of the caatinga and altitude field biomes. In each one of the four areas, 50 samples of ants were collected with a Winkler extractor and anoother 50 with pitfall traps. A total of 191 species distributed in 47 genera was found. The Winkler trap was most efficient in species capture. The communities of the two areas closer to the National Park, at Lençois presented greater similarity between themselves and larger species number, perhaps because they had been less used by humans in the last 40 years, than the two other areas studied, situated in farms and more distant to the Park. The comparative analysis of the similarity indices, calculated from the capture results obtained with the pit-fall traps and Winkler extractor, indicates that the two trees made from the results of all four areas are identical. Although this result was unexpected, it shows that whatever the collection method and the fauna segment studied, the relative similarity between series is respected. If this observation is verified under additional experimental conditions and biomes, it indicates that if the purpose is to use ants as bioindicators, several sampling techniques can be indiscriminately used for the comparative evaluation of ant assemblages, even if different strata are sampled for their fauna, with no impact on the conclusions that can be drawn about their characteristics of degradation or conservation.